1. Field of the Invention
The present invention relates to a technique that makes it possible to express the behavior of particle objects more realistically in a video game.
2. Description of the Related Art
In video games, it is desired to express the environment of a character in a virtual three-dimensional space so that it comes closer to a similar environment in the real world. For example, there is a case in which the environment of a character is expressed by displaying whirling snow on the screen. In this case, expressing whirling snow more realistically makes it possible to display a picture that causes a player to imagine cold winter.
In video games, various objects moving in a virtual three-dimensional space are displayed on the screen. An example of moving objects is a train object. When a train moves in the real world, winds occur around the train. If a train moves in falling snow, snow in the vicinity of the train is influenced by winds that are caused by the movement of the train and its falling directions etc. are changed. It is desired, also in video games, to control the falling directions etc. of snow in accordance with the movement of an object such as a train in a three-dimensional space.
For example, Japanese Unexamined Patent Publication No. Hei. 10-31410 discloses a technique of expressing snow that falls while fluttering by causing fall objects including a plurality of fall bodies as snow to fall with prescribed rotation directions and rotation speeds in an object space. This technique can further express a horizontal wind that varies with the position and time by varying the speeds, directions, and numbers of fall objects based on position and time information in an object space.
An object of the present invention is therefore to provide a technique that makes it possible to express the behavior of particle objects more realistically when influenced by winds caused by the movement of an object.
According to a first aspect of the invention, there is provided a computer-readable recording medium in which a game program for processing an object movement that is processed in a virtual three-dimensional space, the game program causing a computer to execute the steps of moving one or a plurality of regions having prescribed sizes on a screen according to a prescribed rule or a manipulation of a player; displaying one or a plurality of objects on the screen and judging a positional relationship between the object and the region having the prescribed size; determining a condition of movement on the screen of the object in accordance with a variation in the positional relationship between the object and the region having the prescribed size; and moving the object on the screen in accordance with the determined movement conditions.
According to a second aspect of the invention, there is provided a method for processing an object movement that is processed in a virtual three-dimensional space, comprising the steps of moving one or a plurality of regions having prescribed sizes on a screen according to a prescribed rule or a manipulation of a player; displaying one or a plurality of objects on the screen and judging a positional relationship between the object and the region having the prescribed size; determining a condition on movement on the screen of the object in accordance with a variation in the positional relationship between the object and the region having the prescribed size; and moving the object on the screen in accordance with the determined movement condition.
According to a third aspect of the invention, there is provided a game machine which controls, on a display screen, an object movement that is processed in a virtual three-dimensional space, comprising a unit for running a game according to a program; a memory for storing all or part of the program; the display screen on which to display the game that is run by the unit, wherein the unit executes, according to the program stored in the memory, the steps of moving one or a plurality of regions having prescribed sizes on the display screen according to a prescribed rule or a manipulation of a player; displaying one or a plurality of objects on the display screen and judging a positional relationship between the object and the region having the prescribed size; determining a condition of movement on the display screen of the object in accordance with a variation in the positional relationship between the object and the region having the prescribed size; and moving the object on the display screen in accordance with the determined movement condition.